I can't load many pages, I believe all are https. Even known secure sites like Amazon and Paypal, when I try to log in I get an error message.
Secure Connection Failed
The connection to the server was reset while the page was loading.
The page you are trying to view cannot be shown because the authenticity of the received data could not be verified. Please contact the website owners to inform them of this problem.
Learn more…
Report errors like this to help Mozilla identify and block malicious sites
Opaite Mbohovái (1)
There is security software like Avast, Kaspersky, BitDefender and ESET that intercept secure connections and send their own certificate.
http://www.ehow.com/how_11385212_troubleshoot-reset-connection-firefox.html
https://support.mozilla.org/en-US/kb/server-not-found-connection-problem
https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can
https://support.mozilla.org/en-US/kb/firefox-and-other-browsers-cant-load-websites
https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message
https://support.mozilla.org/en-US/kb/connection-untrusted-error-message
http://kb.mozillazine.org/Error_loading_websites
https://www.bing.com/search?q=web+site+access+denied
https://support.mozilla.org/kb/troubleshoot-SEC_ERROR_UNKNOWN_ISSUER
This Connection is Untrusted is sometimes caused because the computer system clock is wrong. Check the time / date / time zone settings.